Microwave Antenna Stop Control for Even and Efficient Heating

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Solution Overview

Problem

Conventional microwave heating devices face challenges in achieving both efficient heating and even heating, as the stopping of a rotating antenna can lead to uneven heating due to prolonged exposure in efficient heating directions, defeating the purpose of rotation for uniform heating.

Innovation Solution

A microwave heating device that includes a heating chamber, a microwave generator, a waveguide, a radiation antenna, a rotary driver, a reflected wave detector, and a controller. The controller stops the radiation antenna's rotation when it faces directions with minimized reflected wave detection amounts, alternating between two different directions to balance heating efficiency and evenness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotating antenna stops at rotation locations with minimal reflectivity values, then heating efficiency is improved, but even heating performance deteriorates

Engineering Contradiction:
Improveheating efficiencyVSAvoideven heating performance
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The antenna stops periodically at multiple rotation locations (first, second, and third locations) with minimal reflectivity values, alternating between these locations to achieve both efficient heating and even heating distribution across the object

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Different rotation locations are selected based on their specific heating characteristics, with the controller alternately stopping at locations that provide complementary heating patterns to ensure overall uniformity

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the rotating antenna rotates continuously, then even heating is maintained, but heating efficiency decreases

Engineering Contradiction:
Improveeven heatingVSAvoidheating efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Instead of continuous rotation, the antenna performs periodic stopping at specific rotation locations where minimal reflectivity occurs, maintaining even heating through alternating positions while significantly improving heating efficiency during stop periods

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The controller pre-calculates and identifies rotation locations with minimal reflectivity values before execution, then stops the antenna at these predetermined locations to optimize heating efficiency from the outset

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the antenna stops for a long time at one rotation location, then heating efficiency is maximized, but uneven heating increases

Engineering Contradiction:
Improveheating efficiencyVSAvoidheating uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The controller alternates stopping between multiple rotation locations (first, second, and third locations) rather than staying at one location, ensuring that heating efficiency is maintained while preventing concentration of heat in single areas

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The stopping duration and sequence at different rotation locations are dynamically controlled to balance heating efficiency with heating uniformity, adjusting the heating pattern based on the specific thermal state of the object

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration improves heating efficiency by maintaining extended exposure in optimal heating directions while mitigating uneven heating by canceling out effects from alternate directions, thus achieving both efficient and even heating.

Implementation Method 1

a reflected wave detector that detects at least part of a reflected wave inside the waveguide

Methodology Applied
Scientific EffectReflected wave detection: Reflection

Implementation Method 2

a magnetron radiates a microwave, which then passes through a waveguide and reaches a heating chamber. This microwave heats an object

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 3

This microwave heats an object (food) placed inside the heating chamber

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP3435737B1Microwave heating device
Publication Date: 2021.04.28 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3435737B1 patent drawingFigure 1
  • EP3435737B1 patent drawingFigure 2A~2B
  • EP3435737B1 patent drawingFigure 3A~3C

AI summary

The present invention has a configuration of controlling motor (15) so as to stop radiation antenna (5) when radiation antenna (5) faces in a direction in which a reflected wave detection amount is minimized and to stop radiation antenna (5) when radiation antenna (5) faces in a different direction different from the direction in which the reflected wave detection amount is minimized. According to this configuration, first, radiation antenna (5) stops when facing in the direction in which the reflected wave detection amount is minimized. This extends a heating time under the most efficient condition, improving a heating efficiency in comparison with when radiation antenna (5) constantly rotates. Second, radiation antenna (5) stops when facing in the different directions. This causes uneven heating when radiation antenna (5) faces in the direction in which the reflected wave detection amount is minimized as well as when radiation antenna (5) faces in the different directions. As a result, the uneven heating is cancelled out by the uneven heating each other caused at different locations. In this way, it is possible to achieve the even heating.